Wikimedia
Wikimedia has 18 million public domain images, a handy resources for designing lecture notes. Can you think of a design for an illustration that you could contribute to wikimedia? At http://en.wikipedia.org/w/index.php?title=Special:UserLogin&returnto=Main+Page&type=signup you can sign up for an account to edit Wikipedia pages. What are some pages that look like they could use some attention?